Hydraulic intensifier



HYDRAULIC INTENSIFIER Filed March 21, 1949 3 Sheets-Sheet l f 750% KM i fla /M a W March 17, 1953 w. R. GROVES 2,631,542

HYDRAULI C INTENSIF I ER Filed March 21, 1949 3 Sheets-Sheet 2 mam, a/r z y/zmz March'17, 1953 w. R. GROVES 2,631,542

HYDRAULIC INTENSIF'IER Filed March 21, 1949 5 Shee'ts-Sheet s W ma mbwmw,

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Patented Mar. 1 7, 1953 HYDRAULIC INTENSIFIER Walter Robert Groves, London, England, assignor to British Industrial Plastics Limited, London, England, a company of Great Britain Application March 21, 1949, Serial No. 82,528 In Great Britain March 25, 1948 6 Claims. (01. 103--51) This invention relates to improvements in hy draulic intensifiers of the continuous delivery double acting difierential piston type in which the changeover. of fluid connections with the cylinder head spaces is effected by main valve means hydraulically controlled by auxiliary valve means automatically operated in synchronism with the. piston. strokes.

One object. of the invention is to provide an intensifier whichis adapted to operate at different degrees of intensification, and another object is to simplify and otherwise improve the construction of the intensifier, especially as to its controlling means.

An intensifier of the aforementioned type according to the invention, comprises fluid connections with the high pressure cylinder head spaces for admitting low pressure fluid to act upon the high pressure pistons during their respective suction strokes so that the full low pressure piston area is effective, and means forclosing these connections, when desired, so that a correspondingly smaller low pressure piston area is efiective. That is tosay, the low pressure piston being, at each side thereof, secured to or formed integrally with a piston rod which is secured to or formed integrally with the high pressure pistons, the effective low pressure piston area may be, as desired, either the full cross-sectional area of the low pressure or only the. annulus which is the difierence between the cross-sectional areas of the low and high pressure pistons.

The said fluid connections with the high pressure cylinder head spaces may be passages leading thereto from the adjacent low pressure cylinder head spaces and provided with non-return valves (automatically closing during the respec tive compression strokes of the-high pressure pis tons) and with means :Eor entirely closing the passages when desired, which latter may be distinct from the non-return. valves or combined with them so as to lock them in the closed position.

The actuation of the means for closing and restoring the. passages may be eiiected manually or automatically in accordance with predetermined requirements of a machine, appliance or system to which high. pressure fluid is delivered.

In order to efiect the filling of. the high pres sure cylinder head spaces during the suction strokes of the respective high pressure'pistons, when the said passages are entirely closed, nonreturn passages of communication are provided between these spaces and, respectively, theopposite, i. e., non-adjacent, low pressure cylinder head spaces. These latter passages are preferably bored through the low pressure piston, the piston rod and the respective high pressure pistons, non-return valves being fitted in the ports of the passages at the faces of the high pressure pistons.

The main control valve means may be of the customary piston type, reciprocated by hydraulic rams under the control of auxiliary valve means, which establish alternately with supply and exhaust a connection to the respective low pres sure cylinder spaces.

The auxiliary valve means which may be used. according to a further feature of, the invention, comprises a rotary 4-way plug valve connected to a supply of fluid under pressure, exhaust, and the spaces behind the aforementioned rams. The spindle of the plug is extended to carry a cam and the valve is mounted so that the cam projects into a recess or gap between abutments on the piston rod of the intensifier which engage the cam and move it one way and the other between limiting stops, during successive piston strokes. Thereby the valve plug is oscillated to change the fluid interconnections at the end of each piston stroke.

The improved intensifier of this invention is useful for various purposes amongst which may be particularly mentioned that of delivering oil or other liquid under alternative. degrees of high pressure to hydraulic moulding presses.

The invention is illustrated by way of example in the accompanying drawings in which:

Figure 1 is a longitudinal part section and part elevation of the intensifier and main valve means;

Figure 2 is an end view of the same;

Figure 3 is a scrap section of a detail shown in Figure 2;

Figure 4 is a section on the line 4-4 of Figure Figure 5 is an enlargement of the section of a detail, 1. e., the auxiliary valve, shown in Figure 4;

Figure 6 is an end view of Figure 5; and

Figure '7 is a section on the line '|-l of Figure 5.

Referring to the drawings, l is a low pressure cylinderblock, 2 and 3 high pressure cylinder blocks, and 4 and 5 the heads of blocks 2 and 3 respectively. A low pressure piston 6 is formed integrally with a piston rod 1 and high pressure pistons 8 and 3. Fluid passages H), H (see Figure 4) are bored through the piston 6, piston rod 7 and, respectively the piston 8,9. These are fitted, in the ports in their faces, with non-return valve I2, [3.

The high pressure cylinder blocks 2, 3 and the heads 4, 5 are bored through toprovide passages l4, l5 communicating respectively with the high pressure cylinder head spaces I5, I1. These passages communicate with the adjacent low pressure cylinder head spaces l8, l9 through spring-loaded non-return ball valves 20, 2|. These valves are adapted to be locked in the closed position or unlocked, at will, by screwed valve spindles 22, 23 with manually operable heads 24, 25. a

The space 26 above the ball valve 2i is in communication with a passage 21 leading to a non-return valve 23 (see Figure 3) mounted in a valve body 29 adapted to be connected to .a pipe (not shown) to deliver for use the liquid under high pressure produced during the working stroke of the high pressure piston 9. Similar provision is made for the delivery of liquid under high pressure produced during the working stroke of the high pressure piston 8.

On the top of the cylinder block I is mounted a main valve block 30 axially bored to accommodate a valve bobbin consisting of piston elements 3!, 32 carried by a piston rod 35, and rams 33, 34 which abut against the valve bobbin. The ports 35, 31 at the ends of the axial bore are con nected, by means not shown, to an auxiliary valve hereinafter described. The block 30 is bored at 38 to provide an inlet for connection to a low pressure liquid supply and is likewise bored at 33 to provide an outlet for connection to exhaust. The valve bobbin is hollow-ed as indicated by the dotted lines 43 and is provided with holes 4| in its end portions.

The block 30 and the block I are bored to form passages 42, 43 connecting the low pressure cylinder spaces l8, IS with the axial bore in the block 30.

The auxiliary valve, which is a rotary 4-way plug valve, is shown in Figures 4-7 as comprising a body portion 53 having a cap 5| and an extension 52 which fits in a recess the block 3. For securing the valve in position bolts are passed through holes 53 in the body 50 and cap 5| registering with holes in the block 3..

The body 50 and extension 52 are bored to accommodate a rotary valve member 54 and valve stem 55. The latter carries a cam 56 movable be- It will be seen from Figure tween stop pegs 51. 4 that the cam 56 lies in the path of abutments 58 on the high pressure piston 3.

The body 50 is also bored to form liquid passages 53, 63, BI and 62, the interconnections of which are controlled by the valve member 54. Passage 5-9 is connected, by external means not shown, to a low pressure liquid supply; passage 30 to exhaust; and passages 61 and 6 2, as hereinbefore mentioned, to the respective ports 36 and 31 of the main valve.

It will be seen from the drawings and from the foregoing description that in operation the auxiliary valve spindle 55 is rocked in synchronism with the piston strokes of the intensifier by reason of the alternate engagements of the abutments 5!! with the cam 56 at the ends of the strokes. The rocking thus imparted to the valve member 54 causes the ports 33 and 31 of the main valve to be alternately supplied with low pressure liquid, and the port not supplied to be connected to exhaust. Accordingly the piston valves 3|, 32 are rapidly reciprocated at the ends of the strokes of the intensifier.

In the position of parts shown in Figures 1 and 4 the high pressure piston 3 has come to the end of a working stroke and the auxiliary valve member 54 has been rocked to change the liquid connections to the main valve so that the port 36 has been supplied with lowpressure liquid and the ram 33 has been operated to move the valve bobbin to the right. Low pressure liquid is ac cordingly supplied from inlet 38 and thence around the piston rod 3 5 and through passages 43 to the low pressure cylinder space l3. At the same time the cylinder space I8 is open to exhaust through passages 42, the hollow interior 40 of the valve bobbin and the holes 4|, and outlet 39.

The low pressure piston 6 therefore moves to the left under the pressure in the cylinder space 19 directly acting upon it and also under the pressure of low pressureliq-uid which passes from the right end of the low pressure cylinder I, through the clearance space between the bore of the high pressure cylinder 3 and the piston rod 1, thence through the ball valve 2! and the passage I5 to the space II, where it acts on the outer face of the high pressure piston 9. This is in the case where the ball valve 2| is free to open. If the ball valve had been locked in the closed position, the piston 6 would be subjected only to the pressure in the cylinder space l'9 directly acting upon it. In such case, as the piston 6 moves to the left the liquid in front of it in the space 18 is passed through the passage ll past the non-return valve l3 to recharge the space I l. When the ball valve 20 is not locked it will be held closed by the high pressure liquid which is being delivered from the space 15 through the passage l4 to the high pressure outlet.

At the completion of the stroke the auxiliary valve is operated in the manner already described, the connections of the main valve are changed over and the piston 6 is moved in the re verse direction.

I claim:

1. A hydraulic pressure intensifier of the continuous delivery double acting differential piston type comprising two high pressure piston and a low pressure piston, cylinders in which said pistons operate, a fluid pressure conduit and an exhaust, main valve means for alternately and respectively connecting opposite ends ofthe cylinder of thesaid low pressure piston to said conduit and to said exhaust, auxiliary valve means connected to one of said cylinders for hydraulically controlling said main valve means, means within said last mentioned cylinder for operating said auxiliary valve means in synchronism with the piston strokes, fluid connections with the cylinders of the high pressure pistons for admitting low pressure fluid to act upon the high pressure pistons during their respective suction strokes so that the area of one high pressure piston and the low pressure piston area are together effective under the action of low pressure fluid for moving the other high pressure piston, and valves in said cylinders between the high and low pressure pistons, operable at will, for entirely closing these said fluid connections so that a correspondingly smaller piston area is subjected to the action of low pressure fluid, whereby diiferent degrees or intensification are obtained,

2. A hydraulic pressure intensifier according to claim 1, in which the last named valves'comprise none-return valves'operable manually to be locked in the closed position.

3. A hydraulic pressure intensifier of the continuous delivery double actin differential piston type comprising two high pressure pistons and a low pressure piston, cylinders in which said pis tons operate, a fluid pressure conduit and an exhaust, main valve means for alternately and respectively connecting opposite ends of the cylinder oi the said low pressure piston to said conduit and to said exhaust, auxiliary valve means extending within one of said cylinders for hydraulically controlling said main valve means, means within said last mentioned cylinder for operating said auxiliary valve means in synchronism with the piston strokes, fluid connections with the cylinders of the high pressure pistons for admitting low pressure fluid to act upon the high pressure pistons during their respective suction strokes so that the area of one high pressure piston and the low pressure piston area are together efiective under the action of low pressure fluid for moving the other high pressure piston, and non-return passages extending through the low pressure piston and the respective high pressure pistons for connecting the cylinders of the high pressure pistons to the respective non-adjacent ends of the cylinder of the low pressure piston.

4. A hydraulic pressure intensifier of the continuous delivery double acting differential piston type comprising two high pressure pistons and a low pressure piston, cylinders in which said pistons operate, a fluid pressure conduit and an exhaust, main valve means for alternately and respectively connecting opposite ends of the cylinder of the said low pressure piston to said conduit and to said exhaust, auxiliary valve means connected to one of said cylinders for hydraulically controlling said main valve means, means for operating said auxiliary valve means in synchronism with the piston strokes, fluid connections with the cylinders of the high pressure pistons for admitting low pressure fluid to act upon the high pressure pistons during their respective suction strokes so that the area of one high pressure piston and the low pressure piston area are together effective under the action of low pressure fluid for moving the other high pressure piston, valves, operable at will, for entirely closing these said fluid connections so that a correspondingly smaller piston area is subjected to the action of low pressure fluid, whereby different degrees of intensification are obtained, and non-return passages extending through the low pressure piston and the respective high pressure pistons for connecting the cylinders of the high pressure pistons to the respective nonadjacent ends of the cylinders of the low pressure piston.

5. A hydraulic pressure intensifier of the continuous delivery double acting differential piston type comprising in combination two high pressure pistons and a low pressure piston, cylinders in which said pistons operate, a fluid pressure conduit and an exhaust main valve means for alternately and respectively connecting opposite ends of the cylinder of the said low pressure piston to said conduit and to said exhaust, auxiliary valve means within one of said cylinders for hydraulically controlling said main valve means, means in said last mentioned cylinder for operating said auxiliary valve means in synchronism with the piston strokes, fluid passages in the cylinder blocks of the high pressure pistons for connecting the cylinders of the high pressure pistons with the respective adjacent ends of the cylinder of the low pressure piston,

, and valves, provided in said passages for entirely closing said passages when desired.

6. A hydraulic pressure intensifier of the continuous delivery double acting difierential piston type comprising a piston unit having two high pressure pistons and a low pressure piston, cylinders in which said pistons operate, a fluid pressure conduit and an exhaust, main valve means for controlling communication between the ends of the cylinder of said low pressure piston and said conduit and said exhaust, means controlled by movement of said piston unit for operating said valve means to alternately and respectively connect opposite ends of the cylinder of said low pressure piston to said conduit and to said exhaust, fluid connections between the respective ends of the cylinder of said low pressure piston and the respective corresponding ends of the cylinders of the high pressure pistons to admit hydraulic fluid into the latter simultaneously with the admission of hydraulic fluid to either end of the cylinder of said low pressure piston, means for cutting on the flow of hydraulic fluid through either of said connections, and means for admitting hydraulic fluid into said end of the cylinder of either high pressure piston when the associated connection is closed.

WALTER ROBERT GROVES.

REFERENES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 329,417 'I'ubbs Oct. 27, 1885 495,334 Hillenbrand Apr. 11, 1893 2,231,307 Wallace Feb. 11, 1941 2,293,076 Ponting Aug. 18, 1942 2,296,647 McCormick Sept. 22, 1942 2,484,884 Hanna Oct. 18, 1949 

